摘要
Background:Sex is an independent risk factor for systemic sclerosis(SSc).Chemokine ligand 4(CXCL4)participates in SSc via multiple mechanisms.In the present study,we investigated the role of CXCL4 in sex-specific lung injury in the bleomycin-induced systemic sclerosis(BLM-SSc)mouse model.Methods:Thirty-two 6-week-old CXCL4^(-/-)C57BL/6J and wild-type(WT)mice were divided into CXCL4^(-/-)male,CXCL4^(-/-)female,wild-type male(WT male),and wild-type female(WT female)groups(n=8 each).BLM-SSc mice were established by subcutaneous injections of 100μL(2 mg/mL of bleomycin,once every other day)for 4 weeks.Thereafter,all mice were sacrificed and the extracted lung tissues were stained with hematoxylin and eosin and Masson's trichrome to evaluate the degree of inflammation and fibrosis.Enzyme-linked immunosorbent assay was used to measure the levels of tumor necrosis factor-αand interleukin-6 in the lung tissue homogenate.In addition,immunofluorescence double staining detected the coexpression of S100 calcium-binding protein A8 and matrix metalloproteinase 7.Two-way analysis of variance was used to examine the independent effects of sex,CXCL4,and their interactions.Results:Compared to CXCL4^(-/-)mice,WT mice had significantly higher infiltration of macrophages and neutrophils,inflammation scores,and fibrosis scores(all p<0.05).Specifically,the degree of macrophage infiltration and fibrosis scores were higher in male mice than those in female mice(all p<0.05).In CXCL4^(-/-)mice,fibrosis scores were higher in males than those in females(p<0.05);however,no significant difference was observed in inflammation scores between the two groups(p>0.05).Compared with that of the CXCL4^(-/-)mice,the levels of tumor necrosis factor-αand interleukin-6 in the lung tissue homogenate were increased in the WT mice with higher levels in the male group.No significant sex-based differences were observed in CXCL4^(-/-)mice(p>0.05).Immunofluorescence double staining revealed a significantly higher number of positive doublestained cells in the WT male than the WT female group;however,no such cells were observed in CXCL4^(-/-)groups.Conclusion:CXCL4 may participate in the pathogenesis of sex-based differential lung injury in the BLM-SSc model.
基金
Nanjing Medical University Science and Technology Development Fund,Grant/Award Number:NMUB20220211
Huai'an Natural Science Research Program,Grant/Award Number:HAP202308。
